26 ANURA 



CHAP. 



preferable name. It is frequentlj' much reduced, even absent, 

 for instance in most Bufonidae and in the Engystomatinae. 

 The posterior so-called sternal part may be termed metosfernu/u. 

 It forms the posterior counterpart of the omosternum. It 

 is attached behind to the epicoracoidal cartilages, or fusing 

 with them forms their ]josterior continuation. It appears 

 mostly in the shape of a style, which is frequently ossified, and 

 Uroadens out behind into a cartilaginous, partly calcified blade. 

 In the Discoglossidae only it diverges backwards into two horns, 

 assuming a striking resemblance to the typical xiphisternum of 

 the Amniota. In young Anura the metasternal cartilage is 

 intimately connected with the ])ericardium, an indication of its 

 being derived not from ribs but from the shoulder-girdle. 



The glenoid cavity is always formed by tlie coracoids and l)y 

 the scapula, but the i)recoracoid often takes part in its forma- 

 tion, for instance in Bufonidae, Hylidae, and Discoglossidae. 



In the fore-limb the humerus has a crest, stronger in the males 

 than in the females ; it assumes extraordinary strength in some 

 C'ystignathidae, notal)ly in the male Leptodactyl us. Eadius and 

 ulna are fused into one bone. The carpalia are originally nine 

 in number : radiale, ulnare, two centralia, and five carpalia distalia, 

 the fifth (if which is reduced to a tiny nodule or to a ligamentous 

 vestige. The primitive condition still prevails in the Disco- 

 glossidae. In most of tiie other Anura the fourth and third 

 distal carpalia, in any case very small, fuse with the enlarged 

 ulnar centrale ; the radial centrale comes, in the Bufonidae and 

 Pelobatidae, into contact with the radius, so that the forearm 

 articulates with three elements as in the Urodela, but with this 

 diffciencc, that the intermedium of the Urodela has been lost by 

 I he Anura. There are five metacarpalia and five fingers, but 

 the elements of the first or tliumb are nearly vestigial, so that 

 tlu! pollnx is reduced to one or twtt nodules, scarcely visible 

 externally. 'J'he normal immlicr of tiie phalanges of the second 

 to iifth fingers is 2, 2, 8, 3. The distal phalanges are generally 

 straight, either ])ointed (ir expanded or with Y or T-shaped ends: 

 itut in the Hylidae, in Jliflanihates amongst the Kanidae, and in 

 (Jeratokyla, one of the Hemiphractinae, the terminal phalanges 

 are produced into curved claws which support the adhesive 

 tiuger-discs. There are, however, many genera of different 

 families, wliich possess finger-discs and have no claw-shaped 



